Frequency control of crossover reactions in concurrent cationic vinyl-addition and ring-opening copolymerization of vinyl ethers and oxiranes: Specific roles of weak Lewis bases and solvent polarity

Kanazawa, Arihiro; Aoshima, Sadahito

Polymer Chemistry, 2015, 6(31), 5675-5682

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Identifier to cite or link to this item: https://hdl.handle.net/11094/100938

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Title
Frequency control of crossover reactions in concurrent cationic vinyl-addition and ring-opening copolymerization of vinyl ethers and oxiranes: Specific roles of weak Lewis bases and solvent polarity
Creator
NRID
1000050621322 1000050621322
ORCID
0000-0002-8245-6014 0000-0002-8245-6014
researchmap permalink
arihiro-kanazawa arihiro-kanazawa
Scopus Author ID
9044912600 9044912600
CreatorName
Kanazawa, Arihiro
NRID
1000050183728 1000050183728
CreatorName
Aoshima, Sadahito
Description
Kanazawa A., Aoshima S.. Frequency control of crossover reactions in concurrent cationic vinyl-addition and ring-opening copolymerization of vinyl ethers and oxiranes: Specific roles of weak Lewis bases and solvent polarity. Polymer Chemistry 6, 5675 (2015); https://doi.org/10.1039/C5PY00152H.
Abstract
Weak Lewis bases and solvent polarity are demonstrated to be highly responsible for the frequency of crossover reactions in the concurrent cationic vinyl-addition and ring-opening copolymerization of alkyl vinyl ethers (VEs) and oxiranes. Weak Lewis bases such as ethyl acetate and 1,4-dioxane promote crossover reactions from isobutylene oxide- or butadiene monoxide-derived propagating species to an alkyl VE monomer, potentially through the more frequent generation of carbocations via the ring opening of the oxonium ion. The specificity of the carbocation that results from the ring-opening reaction - a preference for VE monomers or an aversion to oxirane monomers - is another factor that changes the crossover frequency. Weak Lewis bases, however, have little effect on the relative reactivity of the VE-derived propagating species to each monomer. In contrast, solvent polarity has a significant effect on the promotion of crossover from the VE-derived propagating end to an oxirane, while the frequency of the crossover from the oxirane-derived propagating end is not affected. In contrast to the two oxiranes, the reaction conditions have little effect on the copolymerization using isoprene monoxide, which is an oxirane that generates a more stable, resonance-stabilized carbocation through ring opening. The relative reactivities of VEs and oxiranes under various conditions are discussed in terms of the average number of each monomer unit in one block of the copolymers and in terms of the monomer reactivity ratios.
Publisher
Royal Society of Chemistry
Source Title
Polymer Chemistry
Volume (Issue)
6(31)
Page
5675-5682
Date of Issued
2015-08-21
Language
English
Handle URL
https://hdl.handle.net/11094/100938
PISSN
17599954
eISSN
17599962
Relation.isVersionOf
DOI (Publisher Version)
https://doi.org/10.1039/C5PY00152H
Access Rights
open access
CopyRight
Reproduced from Kanazawa A., Aoshima S.. Frequency control of crossover reactions in concurrent cationic vinyl-addition and ring-opening copolymerization of vinyl ethers and oxiranes: Specific roles of weak Lewis bases and solvent polarity. Polymer Chemistry 6, 5675 (2015); https://doi.org/10.1039/C5PY00152H with permission from the Royal Society of Chemistry.
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Accepted Manuscript
Category
学術雑誌論文 Journal Article